Differences between cardiac memory T wave changes after idiopathic left ventricular tachycardia and ischemic T wave inversion induced by acute coronary syndrome

•Idiopathic left ventricular tachycardia (ILVT) results in cardiac memory (CM)•CM after termination of ILVT mimics ischemic T wave inversion (TWI)•The T wave axis of CM is similar to the QRS complex axis of ILVT•CM after ILVT is typically observed in leads II, III, aVF, aVR, and V4-6•We established diagnostic criteria based on the TWI distribution and QTc interval

BackgroundCardiac memory (CM) after idiopathic left ventricular tachycardia (ILVT) mimics ischemic T wave inversion (TWI) induced by acute coronary syndrome (ACS). We aimed to establish electrocardiography criteria for differentiating the CM from ischemic TWI.Methods and resultsWe evaluated 16 ILVT and 48 ACS patients. We identified TWI after ILVT in 9/16 patients (CM group), typically in leads II, III, aVF, aVR, and V4-6. The characteristics of CM were similar to TWI induced by ACS involving right coronary artery, but the CM group had more TWI in V4 and shorter QTc. The criteria of (1) positive T in aVL, (2) negative or isoelectric T in II, and (3) negative T in V4-6 or (4) QTc < 430 ms were 100% sensitive and 96% specific for the CM group.ConclusionCM after ILVT can be differentiated in most cases from ischemic TWI by the distribution of TWI and the QTc.